Recently, recycled plastic products are used instead of metal for weight reduction. Generally, plastic products produced by, for example, injection-molding using only a thermoplastic resin are poor replacements for metal due to insufficient strength and rigidity thereof.
To solve this problem, plastic products in which a reinforcement material is embedded into a thermoplastic resin are increasingly used for replacement of metal.
Generally, high-strength thermoplastic plastic is divided into Glass Mat Thermoplastic (GMT), Granule-Long Fiber reinforced Thermoplastic (G-LFT), and Direct Long Fiber reinforced Thermoplastic (LTF-D).
Although high-strength thermoplastic plastic reinforces impact strength, flexural modulus and flexural strength using filaments rather than staple composite materials, a continuous fiber-reinforced, high-strength, high-rigidity material is required for some auto-components such as bumper beams, seatbacks, and the like.
Although such reinforcement materials are manufactured in the form of plastic composite sheets, their physical properties vary according to manufacturing methods. Here, thermoplastic plastic composite sheets are manufactured through embedding of woven glass fibers.
Particularly, in the case of producing GMT, although embedment of glass fibers and a polymer are induced through a belt pressing operation, it is difficult for existing techniques to achieve desired strength and rigidity.